1. Field of the Invention
The present invention relates to an electronic cash register. More specifically, the present invention relates to an improved electronic cash register which is adapted to be immune from an inconvenience caused by failure of the power supply therefor.
2. Description of the Prior Art
In a typical prior art electronic cash register, when a customer purchases commodities, the price of each commodity and the code number for identifying the department of each commodity, hereinafter referred to as the department code, are entered by manual operation of numeral keys thereof. These data are stored in respective price and department code storages and each time entry of the price and the department code is completed, for each commodity, the stored data in the said two storages are printed out in a lump. During the consecutive operation of such entries of the price and the department code for each commodity purchased by a given customer, the cumulative total amount of the prices of the respective commodities is obtained for each customer as a result of successive cumulation by means of a summation circuit and is stored in a cumulative total amount storage. After the prices and the department codes of all the commodities purchased by one customer are printed out in order, the cumulative total amount stored in the cumulative total amount storage is printed out in response to a manual operation of a key for instructing the print out thereof.
If and when power failure occurs during the above described consecutive operation of entries of the price and the department code of each of the commodities purchased by the customer, the electronic cash register ceases to operate during the period of the power failure. In such a situation, it is impossible for the operator to know whether the data stored in the said storages which were to be printed out before the power failure were completely printed out. Therefore, it has been a common practice that after the power supply is recovered the data stored in the storages which were to be printed out immediately before the power failure are caused to be printed out again through a repeated entry of the same data of the last entered commodity by a further manual operation.
As described previously, the price and the department code of each of the commodities purchased by the customer are stored in the respective storages and the data stored in these storages are printed out in a lump for each commodity. Also the cumulative total amount is cumulatively stored in a separate storage, throughout the above described entries of the price and department code data, and is printed out by way of a separate step following the print out of the price and the department code data. Therefore, it is desirable, following a power failure and recovery to print out the data which were printed out immediately prior to the power failure. Conventionally, it is necessary for the operator to know which item of those printed out immediately before the power failure, the price and the department code of a particular commodity in a lump or the cumulative total amount, and then to cause the cash register to print out the datas by proper manual operation for selecting the corresponding storage. In addition, the item which is printed out again as described above after the recovery of the power supply is preferably followed by a print out of the letters, for example. RECOVERED immediately after the above described repeated print out in order to allow discrimination of the repeated print out from the print out effected immediately before the power failure. The present invention was achieved in consideration of the above described problems.